Refrigerating apparatus



Aug. 29, 1944. g s. GAUGLER 2,357,099

REFRIGERATYING APPARATUS Filed Feb. 25, 193 9 2 Sheets-Sheet lATTORNEYS- R. S. GAUGLER REFRIGERATING APPARATUS Aug. 29, 1944.

2 Sheets-Sheet 2 Filed Feb. 25, 1939 I Patented Aug. 29, 1944REFRIGERATING APPARATUS Richard S. Gaugler, Dayton, Ohio, assignor toGeneral Motors Corporation, Dayton, Ohio, a

corporation 'of Delaware Application February 25, 1939, Serial No.258,519

,13 Claims.

This invention relates to refrigerating apparatus and more particularlyto two-temperature household refrigerators incorporating a secondaryrefrigerant circuit. I

It has been recognized that the ideal construction for a householdrefrigerator cabinet involves two refrigerating temperatures, one forfreezing ice and a higher temperature for cooling foodstuffs in order tomaintain a high'humidity in the food compartment. The providing or tworefrigerating temperatures makes the refrigerating system morecomplicated and it ha been proposed to employ a secondary refrigerantcircuit for obtaining the higher refrigerant temperature used forcooling the food compartment. A simple secondary refrigerant system doesnot provide a means for temperature control and it has been proposed toemploy a pressure or temperature operated valve for this purpose. Theuse of refrigerant valves in such a secondary circuit is not desirablein all respects, since the valves are comparatively costly tomanufacture and to keep in order. 1

a secondary refrigerant circuit employing inert gas.

It is still another object of my invention to provide a simple meanswhich will trap liquid refrigerant within a portion of the secondarycircuit in order to reduce the cooling effect ,and the amount ofrefrigerant circulated in the secondary circuit.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form ofthe present invention is clearlyshown.

In the drawings:

Fig. 1 is a vertical sectional view taken through a householdrefrigerator cabinet 'of a two-temperature two compartment typeembodying one form of my invention;

Fig. 2 is a sectional view of the temperature evaporator of thesecondary refrigerant circuit. i In one form the secondary refrigerantcircuit is provided with an inert gas and a chamber having its volumecontrolled according to temperatures of the food compartment for varyingthe pressure of the inert gas inthe secondary circuit in order tochange-the evaporating temperature of the secondary circuit. In anotherform of the invention a temperature controlled liquid trap is providedwhich reduces or stops the circulation of liquid refrigerant in thesecondary circuit by withdrawing a portion of the liquid refrigerantfrom active circulation. 7

Referring now to the drawings and more particularly to Fig. 1 there isshown a refrigerator cabinet 20 provided with a freezing compartment 22and a food compartment 24 beneath and insulated from the freezingcompartment 22. A primary refrigerant evaporating mean 26 is provided inthe freezing compartment 22 and has shelves for supporting ice trayswhich may contain water to be frozen.- The primary evaporating means 26forms a portion of a primary refrigerant circuit which includes a sealedmotor-compressor unit 28 for withdrawing evaporated refrigerant from theupper portion of the evaporating means 28 through the suction conduit50. The refrigerant is compressed by the motor-compressor unit 28 andforwarded to a condenser 32 where the compressed refrigerant isliquefied and collected in a receiver 34. From the receiver 34., theliquid refrigerant is forwarded through a liquid supply conduit It to arestrictor 38 which controls the flow of refrigerant into the bottom ofthe primary evaporating means 26.

The operation of the primary refrigerating system is controlled by asnap acting thermostat switch l0 which is connected to and operated inaccordance with the temperature of a thermostat bulb 42 mounted indirect heat exchange relation with the side wall of the primaryevaporating means 26. maintain the primary evaporating means attemperatures below freezing in order that ice may be The switch means 40is so set as to frozen at alltimes. In the conventional refrigerator,the cooling of the food compartment 24 at such a low temperature causesfrost to form upon the evaporating means and also causes the dehydrationof the air and the maintenance of a low relative humidity within thefood compartment.

Therefore, for the refrigerator shown, I have provided a secondaryrefrigerant circuit including a condenser 44 mounted in heat exchangerelation with the side wall of the primary evaporating mean 26 andconnected at its lower and up- 4 per ends with the lower and upper endsof a plate type secondary evaporator 43 provided with a header 48 at itslower edge and a header at its upper edge. This evaporator 48 is formedof two closely spaced metal sheets forming a flat rectangularrefrigerant container which is held in a slanting position in the top ofthe food compartment 24.

If adequate heat transfer surfaces were provided upon both theevaporator and the condenser of the secondary refrigerant circuit it ispossible that if the circuit were merely charged with a volatilerefrigerant that the evaporator 43 might be cooled nearly to thetemperature of th primary evaporating means 26. In order to avoid this,the secondary refrigerant circuit is charged with an inert gas as wellas a volatile refrigerant in order to raise the condensing pressure andtemperature and thereby the evaporating temperature and pressure withinthe secondary circuit so as to maintain the secondary evaporator 46 attemperatures above freezing. The presence of the inert gas in thesecondary refrigerant circuit insures a certain temperature differentialbetween the primary evaporating means 28 and the secondary evaporatingmeans 46.

However, in order to provide a better control of the temperatures in thefood compartment 24 I provide a control means including an adjustablechamber 52 of variable volume which is connected to a portion ofthecondenser 44 by a connecting conduit 54. lows 63 within this chamber 52of variable volume is connected by capillary tubing 56 to a thermostatbulb 58 located in the food compartment 24.

The construction of the chamber 52 of variable volume is better shown inFig. 2 and includes a cup-shaped castin 68 closed by a cap member 62upon which is mounted a large bellows G4 and an inner bellows 66. Eachof these bellows has its open end anchored to and sealed to the capmember 82. The closed end of the large bellows 64 is provided with areinforcing plate 63 which is held against the closed end of the innerbellows 66 bya compression type coil spring which'may have its tensionadjusted by the knurled adjusting screw I2. The interior of the innerbellows 66 is connected to the capillary tubing 53, heretofore referredto, which in turn connects to the thermostat bulb 58 lodged in the foodcompartment 24. The bulb 58 is preferably charged with a volatile liquidso that the inner bellows 66 will expand and collapse according to therise and fall in temperature within the compartment 24. The expansionand col- 1 lapse of the small bellows 66 will expand and collapse thelarge bellows 64 to change the volume of the space 65 between the largeand the inner bellows which space 65 is connected by the tubing 54 tothe condenser .44 of the se ondary refrigerant circuit.

An inner control bel-' By changing the volume of the bellows 44 thevolume of the inert gas in the condenser of the secondary circuit willbe likewise changed so that 'when the bellows 44 is collapsed the volumeof the inert gas in the secondary condenser will be increased toincrease the temperature diflerential between the primary and secondaryevaporators 2i and 44. The collapse of the bellows 34 is accomplished bythe'compression coil spring 10 which will collapse both bellows when thetemperature and pressure within the thermostat bulb 53 is low. Anincrease in temperature of the thermostat bulb is will cause an increasein pressure in the inner bellows and will cause an expansion of bothbellows thus increasing the volume of the bellow -64 to permit areduction in the volume of the inert gas to reduce the temperaturedifferential between the primary and secondary evaporators.

The temperature maintained in the food compartment 24 may be adjusted byemploying the knurled screw 12 to change the tension of the compressionspring 14. Thus if the knurled screw is backed out to releasethepressure of the spring 13 the temperature within the food compartmentwill be lowered. It will be seen that this form of secondary refrigerantcircuit is provided with an adjustable thermostatic control without anyform of valve.

In Fig. 3 there is shown a somewhat different form of two-temperature,two compartment household refrigerator provided with a modified form ofsecondary refrigerant circuit and control which, however, is generallythe same in principle as the form shown in Fig. 1. In Fig. 3 there isshown an inner liner member 323' of a household refrigerator surroundedby insulation and outer walls indicated diagrammatically,

by the dot and dash outline 322. Within the inner liner is a glass plate324 which divides the interior of the cabinet into an upper lowtemperature low humidity compartment or region 326 which contains theprimary evaporating means 328 and a lower high temperature high humiditycompartment or region 330. The glass plate 324 is provided with a rubbersealing gasket 332 at all four edges which extends into sealingengagement with the three walls of the inner liner 320 and the innerface of the door 334. The primary evaporating means 328 is connected toa refrigerant liquefying apparatus, not shown, but which is similar tothat shown in Fig. 1. This liquefying apparatus is controlled by athermostat mounted directly upon the side of the evaporating means 328in order to control the operation of the liquefying means to maintainthe primary evaporating means 323 at freezing temperatures.

In order to cool the lower compartment or region 333, the outer face ofthe inner liner member 320 is provided with serpentine loops 334 of asecondary refrigerant circuit. These serpentine loops 336 are clamped tothe outer face of the inner liner 320 by suitable clamping means andsealing compound may be provided in order to increase the heat transferbetween the loops 336 and the adjacent portions of the inner linermember 320. The uppermost serpentine loop is connected to the secondarycondenser 333 which is clamped to the bottom of the primary evaporatingmeans 323'. This condensin portion 334 is formed of one or moreserpentine loops and a goose-neck type of trap 340 is provided forpreventing any liquid condensing in the condensing P rtion 338 frombeing drained directly into the upper serpentine loop. i

The other end of the condensing portion 338 connects to a section offlexible, tubing designated by the reference character 342 and supportedat its ends by the arms of a bracket 344 which is fastened to the rearwall of the inner liner 328. One end of this flexible tubing 342 is ofcourse connected to the condensing portion 338 while the other'end isconnected to a downwardly extending conduit portion 348 of the secondaryrefrigerant circuit which feeds liquid refrigerant to the serpentinecoils provided upon the bottom of the inner liner 328. It will beunderstood that by raising the'middle portion of the flexible conduit342, liquid refrigerant will be trapped in the condensing portion 338.If the condensing por-' duit 342 is lowered then the refrigerant in thesecondary circuit can circulate and refrigerate the lower compartment338.

This simple means is employed to control the refrigeration provided bythe secondary circuit for the lower compartment 338. In order to do thisa bellows 348 is provided within a casing 358. The interior of thisbellows is provided with a compression type coil spring and the bellows348 is supported between another compressiontype coil spring 352 and anadjusting screw 354 which is adapted to compress the bellows 348 tochange the tension of the compression spring enclosed therein. Thebellows 348 is preferably vcharged with volatile liquid and since thecase 358 is located within the compartment 338 the pressure within thebellows 348 will correspond to the temperature within the compartment338.

One end of the bellows 348 is connected by a link 358 to a bell cranklever 358 which operates a rod 368 extending vertically upwardlyandconnected at its upper end to the mid-point of the flexible tube 348.By this arrangement, when the bellows 348 expands in response to anincrease in temperature in the lower compartment 338, the bell cranklever-358 is pivoted in a clockwise direction about its pivot point tolower the rod 368 and the mid-point of the flexible tubing 342 to permitthe liquid to drain from the secondary-condenser 338 and cool the lowercompartment 338. compartment 338 falls to a predetermined minimum thebellows 348 will collapse and raise the rod 368 and the mid-point of.the flexible tubing 382 to restrict or prevent the draining of thecondensed liquid from the secondary condenser 338 and thus preventfurther condensation and circulation of the liquid refrigerant in thesecondary circuit for the time being.

By manipulating the adjusting screw 354 so as to increase thetension ofthe compression spring within the bellows 348,.the lower compartmentwill be maintained at. a lower temperature; while if the tension of thespring is reduced, the compartment temperature will be raised.

It will be seen that the effective capacity of condensing portion 338will vary with changes in movement of movable portion 342 because, asliquid refrigerant flows out of condensing portion When the temperatureof the- 338'when movable portion 342 is lowered or as liquid refrigerantaccumulates in condensing portion 338 by liquefaction when movableportion 342 is raised, the extent of surface effective to liquefyrefrigerant in'condensing portion 338 increases or decreases. When thecondensing portion 338 has become filled with liquid refrigerant aftermovable portion 342 has been raised, the effective capacity ofcondensing portion 338 .is reduced to a minimum. Then, when portion 342is lowered, liquid refrigerant flows out of condensing portion 338 andthe effective capacity of condensing portion 338 to liquefy refrigerantobviously increases progressively until it reaches its maximum when thecondensing portion is emptied of liquid refrigerant if movable portion342 should be fully lowered. After portion 342 is again raised, liquidrefrigerant accumulates in condensing portion 338 andthe capacity of thelatter to liquefy refrigerant is effectively and progressivelydiminished until reached when portion 338 becomes filled with liquidrefrigerant. Thus I have provided a secondary refrigerant circuit indifferent forms its minimum is without any valves but with a simpleeffective temperature control which can be readily adjusted to provideany desired temperature within a reasonable range within the foodcompartment of a two-temperature household refrigerator.

While the forms of embodiment of the invention as herein disclosed,constitute preferred forms, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A refrigerating apparatus comprising in combination, a primaryrefrigerating system ineluding. a refrigerant liqu'efying unit and anevaporator connected in closed circuit relation,

said evaporator having metal walls in which the refrigerant is located,a closed secondary circuit containing a volatile liquid enclosed in 7metal walls and having an evaporating portion, a portion of the metalwalls of said primary evaporator being in direct metal-to-metal contactwith a. portion of the metal walls of the secondary circuit to form acondensing portion in the secondary circuit, and means for controllingthe temperature of the evaporating portion of the secondary circuit,said means consisting of means for elevating a part intermediate thecondensing portion and the evaporating portion of said secondary circuitabove the plane of the condensing portion thereof whereby said volatileliquid will be trapped in that portion of the metal walls of thesecondary circuit which is in contact with the walls of the primaryevaporator.

2. A refrigerating apparatus comprising in combination, a primaryrefrigerating system including a refrigerant liquefying unit and anevaporator connected in closed circuit relation, said evaporator havingmetal walls in which the refrigerant is located, a closed secondarycircuit containing 'a volatile liquid enclosed in metal walls and havingan evaporating portion, a portion of the metal walls of said primaryevaporator being in direct metal-to-me'ral contact with a portion of themetal walls of the secondary cir- I trapping said volatile ,liquid inthat portion of the metal walls of the secondary circuit which is incontact with the walls of the primary evaporator to thereby control thetemperature of the evaporating portion of said secondary circuit.

3. A refrigerating apparatus comprising, a closed primary refrigeratingsystem including an evaporator, a closed secondary refrigerating circuitcontaining a volatile liquid, said secondary circuit including acondensing portion in heat exchange relationship with said primaryevaporator and an evaporating portion, and means for controlling thetemperature of said evaporating portion of the secondary circuit, saidtemperature controlling means consisting of means for elevating a partof said secondary circuit above at least a part of the condensingportion thereof to trap volatile liquid in the condensing portion ofsaid secondary circuit.

4, A refrigerating apparatus, comprising, a closed primary refrigeratingsystem including an evaporator, a closed secondary refrigerating circultcontaining a volatile liquid, said secondary circuit including acondensing portion in heat exchange relationship with said primaryevaporator and an evaporating portion, and means for controlling thetemperature of said evaporating portion of the secondary circuit, saidmeans consisting of means responsive to the temperature produced by saidevaporating portion of said secondary circuit for elevating a part ofthe secondary circuit above at least a part of the condensing portionthereof to trap volatile liquid in the condensing portion of saidsecondary circuit.

. 5. A refrigerating apparatus comprising in combination, a cabinethaving two food storage compartments provided therein, a closed primaryrefrigerating system associated with said cabinet and including anevaporator located therein for cooling one of said compartments, aclosed secondary refrigerating circuit associated with said cabinet andcontaining a volatile liquid, said closed secondary circuit including acondensing portion in heat exchange relationship with said primaryevaporator and an evaporating portion in heat exchange relationship withthe other of said compartments for cooling the same, and means forcontrolling the temperature of said evaporating portion of saidsecondary circuit, said means consisting of means for elevating a partof said secondary circuit above at least a part of the condensingportion thereof to trap volatile liquid in the-condensing portion ofsaid secondary circuit.

6. A refrigerating apparatus comprising in combination, a cabinet havingtwo food storage compartments provided therein, a closed primaryrefrigerating system associated with said cabinet and including anevaporator located therein for cooling one of said compartments, a

' closed secondary refrigerating circuit associated vwith said cabinetand containing a volatile liquid, said closed secondary circuitincluding a condensing portion in heat exchange relationship with saidprimary evaporator and an evaporating portion in heat exchangerelationship with the other of said compartments for cooling the same,and means for controlling the temperature of said evaporating portion ofsaid secondary circuit, said temperature controlling means consisting ofmeans responsive to the temperature of said other compartment forelevating a part of said secondary circuit above at least a volatileliquid in the condensing portion of said secondary circuit.

'7. A refrigerating apparatus comprising in combination, a cabinethaving an upper food storage compartment and a lower food storagecompartment provided therein, a closed primary refrigerating systemassociated with said cabinet and including an evaporator located thereinfor cooling said upper compartment, a closed secondary refrigeratingcircuit associated with said cabinet and containing a volatile liquid,said closed secondary circuit including a condensing portion in heatexchange relationship with said primary evaporator and an evaporatingportion in heat exchange relationship with said lower compartment forcooling the same, and means for controlling the temperature of saidevaporating portion of said secondary circuit, said means consisting ofmeans for elevating a part intermediate the condensing and evaporatingportions of said secondary circuit above at least a part of thecondensing portion thereof to trap volatile liquid in the condensingportion of said secondary circuit.

8. A refrigerating apparatus comprising in combination, a cabinet havingan upper food storage compartment and a lower food storage compartmentprovided therein, a closed primary refrigerating system associated withsaid cabinet and including an evaporator located therein for coolingsaid upper compartment, a closed secondary refrigerating circuitassociated with said cabinet and containing a volatile liquid, saidclosed secondary circuit including a condensing portion in heat exchangerelationship with said primary evaporator and an evaporating portion inheat exchange relationship with said lower compartment for cooling thesame, and means for controlling the temperature of said evaporatingportion of said secondary circuit, said temperature controlling meansconsisting of means responsive to the temperature of said lowercompartment for elevating a part intermediate the condensing andevaporating portions of said secondary circuit above at least a part ofthe condensing portion thereof to trap volatile liquid in the condensingportion of said secondary circuit.

9. A two-temperature refrigerator comprising a cabinet having a foodstorage compartment, a primary refrigerating system including anevaporator for cooling one region of. said compartment, a secondaryrefrigerating system comprising a cooling portion arranged for coolinganother region of said compartment and a condensing portion disposed inheat exchange relationship with said evaporator and conduits connectingsaid portions, said conduits being free of mechanical restrictions toafford fully open communication at all times between said portions ofpart of the condensing portion thereof to trap the secondaryrefrigerating system and a portion of one of said systems being movablerelative to other portions thereof, and means for moving said movableportion of said one system, said movable portion being so constructedand arranged that movement thereof caused by said means varies theeffective capacity of said condensing portion to liquefy refrigerant.

10. A two-temperature refrigerator comprising a'cabinet having a foodstorage compartment, a primary refrigerating system including an evap-,orator for cooling one region of said compartment, a secondaryrefrigerating system comprising a cooling portion arranged for coolinganother region of said compartment and a condensing portion disposed inheat exchange relationship with said evaporator and conduits connectingsaid portions, said conduits being free of mechanical restrictions toafford fully open communication at all times between said portions ofthe secondary refrigerating system and a portion of one of said systemsbeing movable relative to other portions thereof, and means for causingmovement of said movable portion of said one system, the portions ofsaid secondary system being so arranged with respect to one another andto said evaporator that said movement varies the extent of surface ofsaid condensing portion effective to liquefy refrigerant.

ii. A two-temperature refrigerator comprising a cabinet having a foodstorage compartment, a

primary refrigerating system including an evap-' orator for cooling oneregion of said compartment, a secondary refrigerating system comprisinga cooling portion arranged for cooling another region of saidcompartment and a condensingportion disposed in heat exchangerelationship with said evaporator'and conduits connecting said portions,said conduits being free of me-- chanical restrictions to afford fullyopen communication at all times between said portions of the secondaryrefrigerating system and a portion of one of said systems being movablerela- I erant liquefying and circulating unit and an evaporator havingrefrigerated walls for cooling air in one region of said cabinet, meansincluding a thermal element mounted in direct heat exchange relationshipwith one wall of said evaporator and responsive to the temperaturethereof for controlling operation of said unit to normally maintain theevaporatorbetween predetermined temperature limits, a closed secondaryrefrigerant circuit including a refrigerant evaporating portion forcooling another region of said cabinet and a refrigerant condensingportion, and said refrigerant condensing portion of said second- 7 arycircuit having at least apart thereof located in heat exchangerelationship with said one wall of said primary evaporator and with saidthermal element.

13. A refrigerating apparatus including a cabinet, a closed primaryrefrigerating system associated with said cabinet and including arefrigerant liquefying and-circulating unit and an evaporator having atleast one'upright and other refrigerated walls for cooling air in theupper region of said cabinet, means including a thermal element mountedin direct heat exchange relationship with said upright wall of saidevaporator and responsive to the temperature thereof for controllingoperation of said unit to normally maintain the evaporator betweenpredetermined temperature limits, a closed secondary refrigerant circuitincluding a refrigerant evaporating portion for cooling air in the lowerregion of said cabinet and a refrigerant condensing portion, and saidrefrigerant condensing portion of said secondary circuit having at leasta part thereof located inheat exchange relationship with said uprightwall of said primary evaporator and withl l d thermal element. v

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